Objectives: To explore associations between physical activity (PA) literacy and psychosocial constructs for providing instrumental social support for youth PA. Methods: Ninety-one foster parents completed surveys assessing PA literacy (overall and specific), perceptions of child PA, coordination, PA enjoyment, psychosocial variables: positive/negative beliefs, normative beliefs, perceived behavioral control (PBC), and self-efficacy. Results: Race, negative beliefs, PBC, and foster parent sport involvement were associated with specific PA literacy. Race and education were associated with overall PA literacy. Conclusions: Lower PA literacy is associated with greater negative beliefs and lower perceived control suggesting greater perceived barriers and lower perceived support for/among African Americans and those with less education.